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2x 2S1P 1800mah Tenergy Lipos?

Has anyone tried the Tenergy 1800mah 2s Lipos made for the 1/16 scale stuff?Shown here

I ordered a set and they should be here tomorrow but thought I would ask around. Heck for the set they were only $35 to my door. I will run them on my truck, on the CBA, and get back with the results. Hopefully they don't turn into big balloons

I was running 2s for a bit in my truck, im running the ********* 2s 1800 and they work great. More power than the nimh and better run time. Then I got some ********* 3s 1500 packs and man this thing rips with them! Now I just run 3s.

Will do guys, I'll give a full report once I get them in, I'll just post it in this thread. You can't beat that price, I was originally going to get the maxamps setup but it was going to cost me around $95 to my door for the same series and mah setup. Hopefully I won't be disappointed. If your going to order them before my mini review be sure to use the coupon code to save 12% more, I think it expires on 1/3/2011:

HOLIDAY12

A bummer note, it turns out the company is only 40 minutes from my house and they will let you do pickup to save on shipping. Of course I did not know this upon placing my order, which was estimated to arrive today. I just checked the tracking info for fedex home delivery and is still estimating a delivery of today but doesn't show that the item was even picked up, instead just the electronic information was received, my guess is it will be here tomorrow

The packs seem well built and are your classic soft pack made of a glass tape and a piece of shrink wrap. The wiring is 16ga for the high power wire and is made of 200c silicon. They are quite flexible and seem softer than the stock traxxas nicad pack wiring. The balance leads are JST connectors and also use a soft quality silicon wire. The traxxas HC connectors look to be authentic.

They seem to easily fit in my new summit 1/16th vxl with no issue what so ever. The wires are thin enough to perfectly fit in the stock door with no modificiation.

Initial charging:

I'm a bad reviewer and forgot to measure my packs in their arrival voltage. Pack A2 as it was charged showed that it was quite out of balancing. After about 500mah going in the one cell started limiting my charge holding a voltage of 4.10v while the other was at 3.90v. It took a long time from here since it was so out of balance. Pack A1 was much better and took only about 400 mah and maintained balance through the cycle. Pack A1 gave me a bit of cause for concern but I will see if it will affect the pack in the discharges later.

Battery tests:

Well of course these pack go here pretty late in the day and with a dentist appointment I didnít get to test the packs on the truck yet. But I did run them on the CBA unit. The packs were only charged to 4.10v instead of 4.20 just to add a bit of longevity to the pack. They were discharged at rate of 10 amps and 3.6 amps. 10 amps is equivalent to draining the two packs in the car in just over 5 minutes (20a total), and 3.6a is a half an hour in the car (7.2a total). Individual packs were tested as shown:

The packs heated a decent amount at the continuous 10a going from 69F to about 113F. The 3.6a packs heated from about 69F to 90F. I think 20C continuous might get this packs pretty hot. But realistically the truck will take 30 minutes or more to discharge these packs, which really is just 2C.
They put out between 1.51ah to 1.57ah and since I am not going to 4.2v I am pretty happy with that. Enough of these crazy deep cycles I canít wait to get it in the dirt tomorrow morning.

I will give one last update to the real world performance and run time.

Ok final update:

So today I got to run the packs on my 1/16 summit VXL and it really is a blast. The power is quite unreal and top speed is plenty for me. I didn't think there would be as much top end difference but I was quite wrong, it really hauls!

That being said run time leaves a bit to be desired. I am getting about 23 minutes of running with these lipo packs when charged to 4.15v per cell. The truck is definitely being run harder as I measured the motor holding at about 150F from a starting temp of 68F and ambient 47F. The controller never measured over 95F.

All and all I'm happy with the purchase for the price but would still strive to get longer run times in the end.

So the reason it goes much faster is apparent when you compare the 10a cycle to the traxxas NIMH pack:

The reason your not getting longer runs is your not charging the packs all the way... they will take more Mah to fill them to the 4.2v per cell
If you charge these packs at 1.8amps they will take less than an hour to charge
1hr = 1800mah

The reason your not getting longer runs is your not charging the packs all the way... they will take more Mah to fill them to the 4.2v per cell
If you charge these packs at 1.8amps they will take less than an hour to charge
1hr = 1800mah

You are correct and I should have addressed that. A 4.1v charge will give you about 85% of the rated capacity, 4.15 about 92%. The reason to do this is to allow for long cycle life. Lithium polymer has a fairly high self degration rate that increases with higher voltage. You can actually squeeze a lot more capacity out of a lipo cell by over charging them (very dangerous) but you will get very very crappy cycle life. From what I read using a 4.1v charge and good discharge shut off you can pull off double the cycles.

The reason it takes long than an hour to charge an 1800mah pack at 1800mah is the constant voltage part of the cycle. Lithium cells are charged using constant current then constant voltage (CC/CV). The pack is first charged at a constant current to a given voltage, then that voltage is held as the current is reduced to a set termination amperage. The pack will reach about 80% on the CC stage and take an easily calculated time but the CV stage take much longer to do that last 20% since the current is being reduced.

I will charge the packs up to 4.2 per cell and do one more graph to see what we come up with.

You are correct and I should have addressed that. A 4.1v charge will give you about 85% of the rated capacity, 4.15 about 92%. The reason to do this is to allow for long cycle life. Lithium polymer has a fairly high self degration rate that increases with higher voltage. You can actually squeeze a lot more capacity out of a lipo cell by over charging them (very dangerous) but you will get very very crappy cycle life. From what I read using a 4.1v charge and good discharge shut off you can pull off double the cycles.

The reason it takes long than an hour to charge an 1800mah pack at 1800mah is the constant voltage part of the cycle. Lithium cells are charged using constant current then constant voltage (CC/CV). The pack is first charged at a constant current to a given voltage, then that voltage is held as the current is reduced to a set termination amperage. The pack will reach about 80% on the CC stage and take an easily calculated time but the CV stage take much longer to do that last 20% since the current is being reduced.

I will charge the packs up to 4.2 per cell and do one more graph to see what we come up with.

No one ever said to over charge a lipothat is a very dangerous thing to do, not only will the battery fail, but you can burn down your house or whatever your charging in
charing the packs to 100% will not shorten the life span of the pack, but taking 100% out of the pack will!
one should only take 80% out of any lipo pack to take advantage of longer life cycles, not undercharging them
undercharging them and taking out 100% will shorten the life of the pack

No one ever said to over charge a lipothat is a very dangerous thing to do, not only will the battery fail, but you can burn down your house or whatever your charging in
charing the packs to 100% will not shorten the life span of the pack, but taking 100% out of the pack will!
one should only take 80% out of any lipo pack to take advantage of longer life cycles, not undercharging them
undercharging them and taking out 100% will shorten the life of the pack

I was merely saying that it is possible (again Dangerous) to over charge at the sacrifice of life cycles. I was not saying charging to 4.2v was over charging but it will not provide as many cycles as a lower terminal voltage. It is a fairly well researched aspect of lithium based chemistry:

This is what I was talking about when overcharging (DO NOT ATTEMPT VERY DANGEROUS)

Years ago it was determined that charging LiPolys to only 4.1 volt per cell instead of 4.2 greatly increase the number of cycles they would deliver all other things being equal. Many LiPoly chargers have such an option and many of the very old ones have a LiIon setting which is also 4.1 per cell . Also as mentioned limiting depth of discharge and proper storage goes a long way toward increasing their useful life.

FMA and Kokam conducted extensive LiPoy testing years ago and found that LuPoly life was greatly increased by chatrging to a max of 4.1 per cell. FMA LiPoly chargers have had this option for years and on the Cell Pro 10 and POWERLAB 8 it is listed as Long(er) Life.

Originally Posted by http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Generally speaking, batteries live longer if treated in a gentle manner. High charge voltages, excessive charge rate and extreme load conditions will have a negative effect and shorten the battery life. This also applies to high current rate lithium-ion batteries.

Shallower depth of discharge will help as you have said, but so does lower terminal voltage. I find it easier to use a lower charge voltage since my cuttoff is not programmable on the truck. This will result in longer life on these cells in contrast to charging them to 4.2v with the same cutoff device

I was merely saying that it is possible (again Dangerous) to over charge at the sacrifice of life cycles. I was not saying charging to 4.2v was over charging but it will not provide as many cycles as a lower terminal voltage. It is a fairly well researched aspect of lithium based chemistry:

Shallower depth of discharge will help as you have said, but so does lower terminal voltage. I find it easier to use a lower charge voltage since my cuttoff is not programmable on the truck. []This will result in longer life on these cells in contrast to charging them to 4.2v with the same cutoff device[/]

by your math erlier you have taken our out more than 100% of you packs capacity and that will shorten the life of the packs faster than most anything else
1722mah plus 15% more to charge to the full of 4.2v percell = 1992mah in a 1800mah pack
charging lipos to the safe 4.2v per cell does not shorten the life span of the pack..
every charger on the maket for lipos charges them to 4.2v per cell, and that is not over charging the packs...

If a person wants to deliberately undercharge a pack to help prolong pack life, so be it, however I would rather enjoy the ultimate performance that can only be had from a fully charged pack as opposed to more potential cycles.

If a person wants to deliberately undercharge a pack to help prolong pack life, so be it, however I would rather enjoy the ultimate performance that can only be had from a fully charged pack as opposed to more potential cycles.

I agree, specially when most packs get jacked somehow before 300 cycles anyway...
I never thought about what you said Jakey about not having full potential of a partial charged pack vs fully charged
one cannot get max performance on a partially charged pack

Has anyone tried the Tenergy 1800mah 2s Lipos made for the 1/16 scale stuff?Shown here

I ordered a set and they should be here tomorrow but thought I would ask around. Heck for the set they were only $35 to my door. I will run them on my truck, on the CBA, and get back with the results. Hopefully they don't turn into big balloons